Who Determined the Charge of an Electron?

The electron is a subatomic particle that is known to carry a negative charge. Along with protons and neutrons, these particles make up atoms. The interplay between electrons outside the nucleus of the atom is the phenomenon most capable of producing chemical bonding between elements. In addition to this, electrons are responsible for or play a major role in much of science's most interesting phenomena, such as electricity and magnetism.

History

Electrons and atomic particles may seem like relatively recent discoveries, but their history as scientific knowledge dates back to the mid-1800s. It was at this time that philosopher Richard Laming theorized that the atom consisted of a basic core of matter, and that it was surrounded by additional subatomic particles that encircled the atom and produced electrical charges. It was only a step away for physicist William Weber to take this theory and add to it his hypotheses about electricity and inverse square law. But it was George Johnstone Stoney, in 1874, who narrowed down the laws of electrolysis to the point where he could single out one negatively charged ion and name it the electron. He believed the particles of an atom were fixed indefinitely and could not be removed. It wasn't, however, until later in the century that scientists were able to put all of these theories together to get a full, clear view of the atom and the electrons that make up so much of Earth's matter.

Features

The electron is known to have a negative electrical charge, which is specifically written out as --1.602 x 10-19 C. This is the standard form in which all subatomic particles express their charge. Though our current standards of defining charges relative to one another are inexact, we know that the electron has the exact charge of its opposite, the proton, except for the negative sign. Though there are particles that have been observed to decay over time into lesser or different particles, the electron is thought to be an exception to this phenomenon. At least as far as theory goes, the electron is considered stable.

Size

Through experimentation, the electron has been measured to have a mean radius of 2.8179 x 10-15 m. Scientists use the electron's charge and the theory of electrodynamics to arrive at this number. The mass of an electron is about 9.109 x 10-31 kg. If one were to convert this number through the principle of mass-energy equivalence, it would equal out to a total energy of .511 meV. Using these numbers, scientists are able to compare the electron to its electrical opposite, the proton, and to display a ratio of mass that stands at 1836. This ratio is important, as it comprises one of the constants of physics, and the Standard Model of particle physics depends on this constant never changing.

Effects

The electron is the base on which larger objects of matter depend for their electrical charge. The electron is the particle that balances out the charges of the protons in the nucleus of the atom. Therefore, if there are fewer electrons than there are protons, that object will have a positive charge. The reverse is also true. If the atoms within an object have an equal number of both protons and electrons, the charges will cancel each other out. This means that the net electrical charge of the object is neutral.

Benefits

With almost no exceptions, electrons are the building blocks of every technology we use in the modern world. The entire chemical industry alone depends on our knowledge of and ability to use electrons. We know that the properties of matter depend on the relative charges of electrons in atomic particles; therefore, we can predict the effects of various chemicals and their reactions to each other. Electronics, naturally, is another industry that depends heavily on our use of electrons and the flow of them outside the nucleus of atoms. On a more specific basis, electron beams are used in welding; there is also electron-beam processing, which is used in the health and food industries to sterilize objects.